Merck & Co. has called time on a Sutro Biopharma-partnered IL-2 agonist that was being tested for solid tumors, Fierce has learned.
The candidate, dubbed MK-1484, came out of a 2018 collaboration with Merck to use Sutro’s cell-free protein synthesis and site-specific conjugation platforms to develop novel immune-modulating therapies for cancer and autoimmune disorders.
The companies took MK-1484 into the clinic in 2022 for a trial testing the drug as a monotherapy and in combination with Merck’s megablockbuster PD-1 drug Keytruda in patients with advanced or metastatic solid tumors. The aim was to complete the study this year in order to identify a suitable dose for a planned phase 2 trial.
But Merck confirmed to Fierce this week that the MK-1484 program has instead been scrapped. The company was tight-lipped on the details beyond explaining that the decision was part of a “routine pipeline prioritization.”
The pharma didn’t specifically address Fierce’s question about the implications of the decision on Merck’s exploration of targeting interleukin-2 to treat cancer.
With Merck having already scrapped an autoimmune-focused IL-2 mutein last year, which was originally picked up from its Pandion Therapeutics acquisition, the Big Pharma no longer lists any IL-2 assets in its pipeline. Merck dropped the former Pandion therapy, which was being tested for lupus and vitiligo, after phase 1 results didn’t suggest a clinical benefit.
Multiple companies have bet on IL-2, most notably Bristol Myers Squibb through its huge, ill-fated Nektar Therapeutics deal, without realizing the potential of the cytokine to make cancer immunotherapies more broadly effective.
Takeda and Innovent think they have found a solution with their PD-1/IL-2 alpha-biased bispecific, for which they unveiled some intriguing phase 1 data at the American Society of Clinical Oncology annual meeting in June.
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